Gusset bottom bags in roll form and method of making same



Dec. 19, 1967 A. D. PAXTON 3,358,823

GUSSET BOTTOM BAGS IN ROLL FORM AND METHOD OF MAKING SAME Filed Jan. 16, 1967 2 Sheets-Sheet 1 N1 A LLE/VBPAX mm D INVENTOR. \z

Dec. 19, 1967 A. D. PAXTON 3,358,823

GUSSET BOTTOM BAGS IN ROLL FORM AND METHOD OF MAKING SAME Filed Jan. 16, 1967 2 Sheets-Sheet 2 ALLE/VQPA'X fa/v A T Ta e/v.5 Y

United States Patent 3,358,823 GUSSET BOTTOM BAGS IN ROLL FORM AND METHOD OF MAKING SAME Allen D. Paxton, 8503 Kail Drive, Yakima, Wash. 98902 Filed Jan. 16, 1967, Ser. No. 609,496 6 Claims. (Cl. 206-58) ABSTRACT OF TIE DISCLOSURE A single web of polyethylene, folded against itself with a re-entrant fold in the folded edge and sealed transversely to divide the same into a series of bags and partly severed inwardly from the opposite edge to separate openend portions of the bags, said open-end portions being folded inwardly so that they overlap the balance of the Web, exclusive of said re-entrant fold, said web then be ing rolled on itself from one end thereof to produce a roll which has a substantial uniform density throughout its length.

Background of the invention (1) Field of invention.

Developing a method of presenting gusset bottom bags in roll form to a machine having the function of separating the individual bags from the roll and filling said individual bags thus separated with a product to be packaged therein.

(2) Description of the prior art.

Known prior US. patents include:

(1) Knuetter, 2,265,075, Dec. 2, 1941. (2) Piazze et 211., 2,773,285, Dec. 11, 1956. (3) Alvarez, 3,045,891, July 24, 1962. (4) Hoeppner, 3,147,674, Sept. 8, 1964. (5) Hoeppner, 3,182,430, May 11, 1965.

Knuetter discloses a method of making gusset bottom bags with the same arranged serially in a single web by folding the web on itself as it is drawn lengthwise from a supply roll, refolding the folded edge of the web to produce a re-entrant fold therein, sealing the web transversely at spaced intervals to provide closely spaced sealing zones and severing the web in the areas between the sealing zones of said respective pairs of zones so as to separate the bags from the web.

Alvarez discloses a method of forming a continuous series of bags in a continuous polyethylene web by folding this web on itself, without forming a re-entrant fold in the folded edge thereof, sealing the web transversely with pairs of sealing zones spaced closely from each other and having perforations between said sealing zones which permit the bags to be separated from the web manually as shown in FIGURE 19. One of the features of the Alvarez invention is that the web containing the continuous series of envelopes may be rolled upon itself from one end thereof to produce a roll of uniform density throughout its length so that this mode of packaging may be used in supplying the individual bags embodied in the entire web to a machine for filling said bags with a product.

Summary of the invention The present invention provides a continuous series of gusset bottom bags in roll form which is so produced that when the roll is made from the web embodying the bags it will have a uniform density throughout the length of the roll and thus permit the roll to be effectively used in the delivery of the bags embodied in the roll one-byone to a machine for filling the individual bags and separating them from the roll. I

The invention also embraces a novel method by which Patented Dec. 19, 1967 gusset bottom bags may be embodied in a roll and yet Brief description of the dnawings The manner of accomplishing the foregoing objects as well as further objects and advantages will be made manifest in the following description taken in connection with the accompanying drawings in which:

FIGURE 1 is a diagrammatic plan View of a web of polyethylene film or the like being fed along a given path in the performance of the method of the invention.

FIGURE 2 is an enlarged diagrammatic cross-sectional view of said web taken on the line 2-2 of FIGURE 1.

FIGURE 3 is a diagrammatic perspective view of the step in the method shown in FIGURE 1 in which transversely disposed pairs of seals are formed in the initially folded web to unite overlying layers of the Web together along closely spaced transverse lines, sever said web in the area between the seals of each of said pairs adjacent one edge of said web, and form a series of perforations in the areas between the seals of said pairs in the balance of the web whereby upper portions of bags formed in said web are entirely separated while lower portions of said bags which embody a gusset bottom in each of the bags are separated by a perforated zone in the web which may be parted by tearing each bag from the bags adjacent thereto.

FIGURE 4 is a diagrammatic partial side elevational view of the roll of the invention and is taken on the line 44 of FIGURE 1.

FIGURE 5 is a fragmentary enlarged elevational view of the pairs of sealing zones produced in the preferred method of the invention, the cut which completely severs the web material between certain portions of said sealing Zones, and the perforations which are formed between other portions of said zones and which afford the opportunity of readily separating each bag in the roll from a bag adjacent thereto by a simple tearing process.

FIGURE 6 is a diagrammatic sectional view of the sealing-severing-perforating blade shown in FIGURE 3 and is taken on the line 6-6 of the latter figure.

FIGURE 7 is a view similar to FIGURE 2 and is taken on the line 7-7 of FIGURE 1 so as to illustrate how the folding of upper portions of the bag in said roll against lower portions of said bags but excluding the portion having a re-entrant fold therein, causes the roll produced by rolling the web thus folded to have a uniform density throughout the length of the roll.

FIGURE 8 is a view similar to FIGURE 1 and illustrates the performance of the method of the invention to produce an endless series of gusset bottom bags in roll form in which the individual bags are held in said roll united consecutively with each other by a modified form of perforating means.

FIGURE 9 is a View similar to FIGURE 3 and illustrates the sealing, severing and perforating steps in the method of the invention in producing the type of roll shown in FIGURE 8.

FIGURE 10 is an enlarged fragmentary elevational view illustrating the surface of the web employed in the modified form of the method of the invention illustrated in FIGURES 8 and 9 and showing how the perforations provided in said form of the method comprise short groups of relatively small perforations separated by relatively long slits in the web material and in which the pairs of seals extending transversely of the web and which separate adjacent bags in the web from each other are relatively narrow and unite the overlying layers of the web merely at the edges of said slits and said perforations.

3 FIGURE 11 is a diagrammatic cross-sectional view taken on the line 1111 of FIGURE 9 and illustrates the type of heated blade employed in the steps shown in FIGURE 9 to produce the result illustrated in FIGURE 10.

Description of the preferred embodiment This embodiment comprises a roll 14 which is illustrated, together with the method of making said roll, in FIGURE 1. As shown in this view, roll 14 comprises a continuous series of individual gusset bottom bags 15 which are formed from a web 16 of sheet polyethylene or the like by passing this web in the direction of arrow 17 through a series of processing steps which may be described as follows:

The initial steps of this method precede those illustrated in FIGURE 1 and are not disclosed herein because these are clearly shown in FIGURE 3 of the above Kneutter patent. By reference to this view of this patent it may be seen how the web 16 is originally formed and wound, in single sheet thickness, about a core to form a supply roll of said web from which the latter is drawn as the first step in performing the process of the present invention. The first change that takes place in the web, as this is drawn from said supply roll, is the folding of the web into two layers, a lower layer 18 and an upper layer 19 which overlaps the lower layer with the exception of a narrow marginal portion 29 of the lower layer. The next step is the deformation of the fold between the upper and lower layers 18 and 19 to produce a re-entrant fold 21 which eventually forms the gusset bottom 22 of each of the bags 15. The steps of the present method described so far are identical with similar steps disclosed in the aforesaid Kneutter patent. From this point onward however the steps employed in the present method are novel over all the prior art.

The first of these novel steps consists in applying transversely to the web 16 at uniform intervals a combination heated cutter-sealer-perforator blade 23 which is shown in cross-section in FIGURE 6 and in perspective in FIG- URE 3. The blade 23 is slightly longer than the transverse dimension of the web 16 after this has been folded against itself and after the re-entrant fold 21 has been made at the folded edge of the web. The blade 23 has a bottom sealing face 24 from a central portion of which extends a cutter knife 25 and a perforating knife 26. The knife 25 has a continuous edge for forming a cut and the knife 26 is serrated for forming a line of very small and closely spaced perforations. In the performance of the present method, the blade 23 is maintained at a predetermined temperature by a thermostatic control and mechanism (not shown) may be provided for lowering this blade in a transverse relation with the web 16 at regular intervals during the passage of this web beneath said blade so as to divide said web into individual bags 15. Each time the blade 23 so descends on the web 16, the cutting knife 25 forms a narrow cut 31 in the web and the perforating knife 30 cuts a series of small perforations 32 in said web. At the same time the sealing face 24 is brought to bear pressurably against the web 16 so that the heat applied by the blade 23 along said sealing face is effective in sealing together the various layers in the folded web 16 where they are thus compressed beneath the blade 23. Closely spaced transverse sealing zones 33 are thus provided which extend across the entire width of the web 16 at opposite sides of the slot 31 and the row of perforations 32.

The length of the cut 31 thus formed by each impression of blade 23 on the web 16 is equal to (the entire width of the web, minus the width of re-entrant fold 21) divided by 2. The seal zones 33 formed by successive impressions of the blade 23 are thus seen to divide the web 16 into an endless series of bags 15, the open ends of these bags being located at the marginal area 20 of the web. The upper or open end portions 34 of adjacent bags 15 are freed from each other by the cuts 31 and are readily foldable about a fold line 35 which is parallel with the web 16 and intersects the inner ends of cuts 31.

The next step in the present method comprises folding the divided upper portion 34 of each bag 15 about the fold line 35 so that portions 34 lie against those areas of these bags which lie between said fold line and the re-entrant fold 21. This folding of portions 34 may be done manually or by machinery and in commercial performance of the method will preferably be done mechanically.

Referring now to FIGURE 7 it is to be noted that a folding of open end portion 34 of the bag 15 about the fold line 31 against the balance of the web 16 (but so as not to overlay the re-entrant fold 21), produces in the web (thus narrowed transversely) a uniformity in the thickness of the web across its entire transverse dimension. In other words the web is now uniformly four thicknesses deep throughout its width with the inconsiderable exception of the area in which the marginal area 20 at the end of each bag is located in the folded web. Thus when the final step of winding the web 16, folded in this manner, into the form of a roll 14, takes place, each turn of the web added to the roll 14 adds approximately identically the same radial thickness to all portions of the roll throughout its axial dimension. This means that no matter how long a web 16 is wound upon itself from one end to form a roll 14, this roll remains in true cylindrical form and has uniform density throughout its length. The roll 14 thus serves as a practical means of storing a large number of individual bags 15 formed by the method of this invention from a single web 16 pending the demand for delivery of such bags one at a time to a machine designed to use the same.

Gbviously, any machine of the latter category has means for unfolding the folded open end portion 34 of each bag 15 immediately prior to filling this bag and separating it from the balance of the web 16. Such means for utilizing the roll 14 and the bags 15 embodied therein, are no part of the present invention.

When the time comes to separate one of the bags 15 from another bag adjacent thereto this may be done by the application of a cutter either hot or cold which will sever the webs intervening between perforations 32 or by merely pulling the two bags apart causing a rupture of these webs which are purposely made with such a narrow dimension as to make this easy to accomplish.

Referring now to FIGURES 8 to 11 inclusive, a modified form of the roll of the invention and the method of making the same which are illustrated in these views will now be described. Where numerals used in describing the preferred embodiment of the invention may fittingly be applied in the description of the modified form thereof these numerals will be used in describing the latter with prime added. The roll 14 embodies a series of bags 15' which are formed by the performance of various process steps upon a polyethylene web 16'. These steps are identical to those already described in the above disclosure of the preferred embodiment of the roll and method of the invention with the exception that a cutter-sealer-perforator blade 23' is employed in dividing the web 16 into individual bags 15. The blade 23 is relatively narrow and lacks the seal forming shoulder 24 which is found on the lower edge of cutter-sealer-perforator blade 23 shown in FIGURE 6. As a result, wide seal zones 33 which are provided in the web 16 are lacking in the processing of web 16. The blade 23 has a cutting knife 25' a spaced series of relatively short groups of perforating knives 36 and secondary cutting knives 37 which are located between the groups of perforating knives 36 as shown in FIGURE 9. In the process of forming modified roll 14 of the invention, the blade 23' is reciprocated vertically into pressural relation with the web 16' at the proper intervals to divide said web into a series of individual bags 15. The cutting knife 25 in each of these engagements cuts a slot 38 in the upper and lower layers of the web 16 therebeneath and seals these two layers together along the edges of said slot. At the same time the contact of the perforating knives 36 with web 16' forms groups of small perforations 39 while sealing together, at the borders of these perforations, the layers of the web 16' engaged by said perforating knives.

Simultaneously with this operation, of course, the secondary cutting knives 37 form slots 40 which extend between the groups of perforations 39 formed by the knives 36. Heat from the cutter-sealer-perforator blade 23' seals together the various layers in the web 16' which are penetrated by this blade in forming slots 38 and 40 and groups of small perforations 39 said seals being accomplished in zones immediately adjacent to edges of each of these slots and perforations. As shown in FIGURE these seal zones are very narrow yet they are adequate to seal the entire side edges of the individual bags formed from the web 16' by the modified method of the invention being described. The perforations 39 are also close enough together so that when adjacent bags 15 are cut or torn apart by severing or rupturing the webs between adjacent perforations 39, this separation does not destroy the effectiveness with which opposite side edges of each bag 15 are individually sealed. The perforations 39 are close enough together so that the sealing of the layers of the web 16', which extends outwardly from each of these perforation toward the perforations adjacent thereto, form substantially a continuous seal along a transverse line through each of these groups of small perforations 39 so that when the webs located between adjacent pairs of perforations are ruptured to separate the bags, each individual bag retains a complete seal along the areas of each of its sides disposed opposite the groups of small perforations 39.

In the modified form of the method of the invention shown in FIGURES 8, 9, 10 and 11, the upper open end portions 34' of the respective bag 15' are folded about fold line 35' in a similar manner as is done in the preferred embodiment of the method of the invention so that when the folded web 16 is wound on itself from one end thereof to form a roll 14 this roll has a substantially uniform density throughout its axial dimension.

The principal advantage of the modified form of the method of the invention is in the increased ease afforded by the reduced amount of material in the web 16' which must be ruptured to separate adjacent bags 15' from each other. This is accomplished by eliminating most of the webs separating adjacent small perforations in the preferred embodiment of the invention by reducing the perforated areas separating adjacent bags by limiting these areas to three short groups of perforations 39 and then separating these groups by slots 40 in which the juxtaposed side areas of the adjacent bags are of course entirely separated.

I claim:

1. Gusset bottom bags in roll form comprising:

a single web of polyethylene or the like folded against itself along a longitudinal fold :line to produce a W cross-section re-entrant fold having a pair of outer external folds and a central internal fold;

a series of pairs of seals extending transversely of said folded web to unite the overlapping layers thereof,

said pairs being disposed at intervals to divide said folded web into a consecutive series of bags with open ends at the opposite side of said web from the side having said re-entrant fold,

said folded web being partially severed inwardly from said opposite side thereof along lines located between the respective seals of said pairs of seals,

for distances approximately one-half the difference be tween the width of said folded web and the width of said re-entrant fold thus separating open end portions of said bags from each other along their juxtaposed bag sides, said separated bag portions being folded along a medial line parallel with said web to overlie respectively unseparated portions of said bags, with the exception of those portions embodying said re-entrant fold,

said web, with said separated bag portions thus folded thereagainst, being rolled on itself from one end thereof,

the approximately uniformity in the distribution transversely of the bulk of said folded web effecting a corresponding uniformity of density of the roll thus produced by rolling said web.

2. Gusset bottom bags in roll form as recited in claim 1 wherein:

the material of said web in the areas between the respective seals of said pairs of seals which are not severed as aforesaid are provided with perforations which weaken said web so as to allow individual bags or groups of bags to be readily separated from said web.

3. Gusset bottom bags in roll form as recited in claim 2 wherein said perforations are relatively small and closely spaced from each other.

4. Gusset bottom bags in roll form as recited in claim 2 wherein:

said perforations include short groups of relatively small closely spaced holes and relatively long cuts located between said groups.

5. The method of making gusset bottom bags in roll form which comprises:

drawing a single web of polyethylene from a supply roll;

folding said web on itself as it is thus drawn;

forming a re-entrant fold in the folded edge of said web; heat sealing together the overlying layers of said folded web along closely spaced pairs of narrow zones extending transversely of said web, said pairs being located at spaced intervals to divide said web into a series of gusset bottomed bags;

partially severing said folded web between the sealed zones of said respective pairs of such zones for a substantial distance inwardly from the web edge which is disposed oppositely from the web edge occupied by said re-entrant fold, thereby separating open-end portions of said bags from each other along their juxtaposed bag sides,

folding said open-end bag portions, thus separated, to

overlie respectively unseparated portions of said bags but excluding the re-entrant fold portions of said bags, and

rolling said web on itself from one end thereof to produce a roll which has a substantially uniform density throughout its length.

6. The method of making gusset bottom bags in roll form as recited in claim 5 including the step of providing perforations in those portions of the areas between said sealed zones which are not severed, to permit ready separation of the bags comprised in said web.

References Cited UNITED STATES PATENTS 2,265,0 12/1941 Knuetter 93-35 2,773,285 12/ 1956 Piazze et a1 22969 X 3,045,891 7/ 1962 Alvarez 229-69 3,147,674 9/ 1964 Hoeppner 93-35 3,182,430 5/1965 Hoeppner 5329 MARTHA L. RICE, Primary Examiner. 

1. GUSSET BOTTOM BAGS IN ROLL FORM COMPRISING: A SINGLE WEB OF POLYETHYLENE OR THE LIKE FOLDED AGAINST ITSELF ALONG A LONGITUDINAL FOLD LINE TO PRODUCE A W CROSS-SECTION RE-ENTRANT FOLD HAVING A PAIR OF OUTER EXTERNAL FOLDS AND A CENTRAL INTERNAL FOLD; A SERIES OF PAIRS OF SEALS EXTENDING TRANSVERSELY OF SAID FOLDED WEB TO UNITE THE OVERLAPPING LAYERS THEREOF, SAID PAIRS BEING DISPOSED AT INTERVALS TO DIVIDE SAID FOLDED WEB INTO A CONSECUTIVE SERIES OF BAGS WITH OPEN ENDS AT THE OPPOSITE SIDE OF SAID WEB FROM THE SIDE HAVING SAID RE-ENTRANT FOLD, SAID FOLDED WEB BEING PARTIALLY SEVERED INWARDLY FROM SAID OPPOSITE SIDE THEREOF ALONG LINES LOCATED BETWEEN THE RESPECTIVE SEALS OF SAID PAIRS OF SEALS, FOR DISTANCES APPROXIMATELY ONE-HALF THE DIFFERENCE BETWEEN THE WIDTH OF SAID FOLDED WEB AND THE WIDTH OF SAID RE-ENTRANT FOLD THUS SEPARATING OPEN END PORTIONS OF SAID BAGS FROM EACH OTHER ALONG THEIR JUXTAPOSED BAG SIDES, 